Costa Mesa, CA: 48 Health Violations — 55/100 (2026)
3 ZIP codes · 5 water systems · Updated 2026-06-03
Safe water is the norm across most of Costa Mesa, CA — but documented violations push the city to the middle safety tier.
How Costa Mesa Compares
Data: EPA SDWIS Last verified: 2026-06-03
What You Should Know About Costa Mesa Water
- Your city's water systems recorded 84 violations in the past 5 years.
- Homes built before 1986: 78% — older plumbing may contain lead solder.
- Estimated remediation: $1,733 per household.
- CDC health risk index: 10.23.
Who Supplies Your Water in Costa Mesa
In Costa Mesa, CA, residential water supply is distributed across multiple utilities rather than concentrated in one. The 3 leading providers out of 5 tracked systems each control their own infrastructure, file separate EPA compliance reports, and set independent rate schedules.
Overview
We track water quality and home safety data for 3 ZIP codes in Costa Mesa, California (population ~111,320), covering 5 community water systems serving approximately 623,822 people region-wide.
3 of 3 ZIP codes (100%) have recorded EPA violations. 48 health-based violations documented.
Home Safety Score
Average Home Safety Score for Costa Mesa: C (55/100)
The score combines three factors:
| Factor | What It Measures |
|---|---|
| Water Quality | EPA violations and compliance history |
| Lead Levels | 90th percentile lead concentration vs EPA action level |
| Radon Risk | EPA radon zone classification |
Water Sources
Costa Mesa water systems draw from: Groundwater, Surface water.
Lead & Copper
- Lead data: not yet available for Costa Mesa
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 3 (Low Risk)
- Zone 1 (High): 0 ZIP codes
- Zone 2 (Moderate): 0 ZIP codes
- Zone 3 (Low): 3 ZIP codes
Top Contaminants
| Contaminant | Category | Violations | ZIPs Affected |
|---|---|---|---|
| Contaminant 1032 | Other | 68 | 3 |
| Contaminant 1028 | Other | 44 | 3 |
Areas with Most Violations
| ZIP Code | Safety Score | Violations | Health-Based | System |
|---|---|---|---|---|
| 92626 | D | 28 | 16 | Mesa Water District |
| 92627 | C | 28 | 16 | Mesa Water District |
| 92628 | C | 28 | 16 | Mesa Water District |
All ZIP Codes in Costa Mesa
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
Updated daily.
Health Outcomes in Costa Mesa
Source: CDC PLACES (County-level estimates). Water contamination can correlate with respiratory and chronic health conditions.
Compared to National Average
Vertical line = national average. ■ Above national · ■ Below national
Top Contaminants in Costa Mesa Water
Based on EPA violation records. Check your ZIP code report for system-specific contaminant data.
Housing & Infrastructure in Costa Mesa
With 78% of homes built before 1986, lead solder in plumbing is a potential concern. The EPA banned lead solder in 1986, but many older homes retain original plumbing.
Source: U.S. Census Bureau American Community Survey (ACS).
Housing Age Profile
Reading the housing age data for Costa Mesa — median build year 1969 — the overriding implication is that the plumbing materials inside a typical home here reflect pre-1986 construction standards. In practical terms, that means lead-soldered copper joints are common across much of the housing stock. Where those materials are present, water can leach lead as it moves through joints — a pathway that corrosion control treatment under federal rules is designed to reduce, though it cannot eliminate lead risk where the plumbing materials themselves contain lead.
Over half of homes in Costa Mesa were built before 1986, when lead solder was banned. Older plumbing may leach lead into drinking water, especially with corrosive water chemistry.
Source: U.S. Census Bureau ACS B25034.
Cost Context: What Remediation Means for Costa Mesa Homeowners
Within the Costa Mesa market, estimated remediation claims a small portion of typical property equity — the financial burden is proportionally low.
Remediation costs in Costa Mesa are relatively low compared to home values. The $1,033–$3,233 estimated range is a small fraction of median property value. Home values are 46% above the California average.
Lead Exposure Risk for Children in Costa Mesa
Why children are most at risk: The CDC states there is no safe level of lead exposure for children. Children under 6 absorb lead more readily than adults, and even low levels can cause developmental delays, learning difficulties, and behavioral problems.
Pulling a tap sample fills the gap that utility data cannot close, particularly here where 78% of housing dates from the pre-rule era and citywide monitoring sits at or above the regulatory mark in Costa Mesa.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Flood & Climate Risk in Costa Mesa
Multiple flood events have been recorded for Costa Mesa through the NFIP — 134 claims in total, with 67% of ZIP codes in FEMA-designated zones — pointing to a flood exposure profile that merits inclusion in a water quality assessment without reaching high-severity planning territory.
Costa Mesa has a moderate flood history with 134 FEMA claims averaging $5,906 per payout. 67% of ZIP codes fall within FEMA flood zones. Flood events can contaminate drinking water and overwhelm treatment systems.
How flooding affects water quality: Flood events can introduce sewage, agricultural runoff, and industrial chemicals into water supplies. Even after floodwaters recede, contamination can persist in wells and aging infrastructure. Flood damage can add significantly to the estimated <strong>$1,733</strong> remediation cost per household.
Residents in flood-prone areas should consider flood insurance even outside FEMA zones — over 25% of flood claims come from low-to-moderate risk areas. After any flood event, test your water before drinking.
Source: FEMA National Flood Insurance Program (NFIP) claims data, FEMA flood zone designations.
What You Can Do in Costa Mesa
- Test your water at home. City-level data shows averages — your tap may differ. NSF-certified test kits cost $20-40 and give results in days.
- Install a certified water filter. Filters rated for Contaminant 1032 can reduce the most common contaminant found in Costa Mesa's water.
- Check your home's plumbing. With 78% of homes built before 1986, lead solder is a real possibility.
Deep Dive Reports
Detailed analysis for Costa Mesa, CA